Patient Support Pads for Use in Detecting Lymphedema Through X-Ray Scans

ABSTRACT

A system for detecting lymphedema comprising a dual energy x-ray absorptiometry system and one or more spacer pads disposed with a field of view of the dual energy x-ray absorptiometry system. The dual energy x-ray absorptiometry system comprising an x-ray source and a patient support platform, wherein the patient support platform is configured to receive a patient in a supine position with the x-ray source disposed above the patient support platform. The one or more spacer pads configured to be positioned body parts of the patient.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.13/894,700, filed May 15, 2013, allowed, which claims priority toprovisional U.S. Patent Application Ser. No. 61/648,742, titled“Apparatus and Method for Detecting Lymphedema Using X-Ray Scans,” filedon May 18, 2012, the disclosure of which is herein incorporated byreference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to the detection of lymphedema using x-rayscans, e.g., with use of a dual-energy absoptiometry (DXA) system.

2. Background of the Art

For treatment of invasive breast cancer, surgeons generally remove someof the lymph nodes under a patient's arm during a lumpectomy ormastectomy. The reason for lymph node removal is twofold. Because thelymphatic system is a whole body system, lymph nodes may beintentionally removed in order to reduce the opportunity for spread ofcancer cells throughout the body. In addition, lymph nodes may beunintentionally removed because they are interwoven with axilla breasttissue within the body; removal of breast tissue unavoidably results inremoval of lymph nodes.

The removal of lymph nodes may cause a lymphatic obstruction whichblocks the lymph vessels that drain fluid from tissues throughout thebody and allow immune cells to travel where they are needed. A lymphaticobstruction may in turn cause lymphedema, i.e., swelling due to theblockage of the lymph passages. Lymphedema is a feared complication ofcancer treatment and one that negatively impacts survivorship.Lymphedema is a chronic disease that usually requires lifelongmanagement as it may result in complications such as chronic wounds andulcers, skin breakdown and lymph-tissue types of cancers. Earlydetection of lymphedema may reduce the amount of swelling, discomfortand risk for a patient.

Whole body scanning is one approach to estimating body mass or assessingassorted body compositions, such as distribution of fat, lean mass,bone, and fat mass index. One problem with using a whole body scanningsystem to estimate body mass involves the delineation of body partsduring the scan. In particular, when a patient lies in the supineposition, there is a tendency for extra chest tissue, such as thepatient's breasts, to fold over onto the arm. Similarly, if thepatient's feet and legs are spaced too close together, there may bedifficulties delineating the individual masses of the legs. Overlappingtissue during the scan can decrease the accuracy in body massmeasurements for the individual body parts.

SUMMARY

What is needed, then, is an apparatus and/or method to assist indelineating body parts when a patient undergoes a body scan, e.g., usinga DXA scanner. It is realized that the ability of an x-ray body scan toaccurately and precisely measure body mass may be leveraged for earlydiagnosis of lymphedema, thereby enabling early treatment and helping toreduce complications associated with the disease. Early signs oflymphedema may be detected through an increase in body mass resultingfrom the accumulation of fluid in patient's appendages. Because x-rayscanning provides accurate measurement of body mass, an easy andreliable method for early detection of lymphedema is provided.

According to one aspect, the invention relates to a system for detectinglymphedema comprising a dual energy x-ray absorptiometry systemcomprising an x-ray source and a patient support platform. The patientsupport platform is configured to receive a patient in a supine positionwith the x-ray source disposed above the patient support platform. Thesystem also comprises one or more spacer pads disposed with a field ofview of the dual energy x-ray absorptiometry system, the one or morespacer pads configured to be positioned body parts of the patient.

The foregoing aspect can include any one or more of the followingembodiments. The one or more spacer pads can comprise low x-rayattenuation material. The low x-ray attenuation material can beradiographic foam. Each of the one or more spacer pads can be uniformlyconstructed. The system can further comprise a sanitary cover to covereach of the one or more spacer pads, the sanitary cover made of clearmaterial. A height of each of the one or more spacer pads can exceed amaximum body thickness of the patient. The one or more spacer pads canbe rigid so that the one or more spacer pads does not flex during use.The one or more spacer pads can be low weight. The one or more spacerpads can be positioned between at least one of an arm and trunk of thepatient or legs of the patient.

In another aspect, the invention relates to a method of detectinglymphedema comprising providing a dual energy x-ray absorptiometrysystem, the system comprising an x-ray source and a patient supportplatform, positioning a patient in a supine position on the patientsupport platform such that the patient is between the x-ray source andthe patient support platform, and positioning a spacer pad between bodyparts of the patient such that the spacer pad is positioned within afield of view of the dual energy x-ray absorptiometry system.

This aspect can include any one or more of the following embodiments.The method can further comprise scanning the patient using the dualenergy x-ray absorptiometry system to detect lymphedema. The spacer padcan comprise low x-ray attenuation material. The low x-ray attenuationmaterial can be radiographic foam. The spacer pad can be uniformlyconstructed. The spacer pad can be covered by a sanitary cover, thesanitary cover made of clear material. A height of each of the one ormore spacer pads can exceed a maximum body thickness of the patient. Thespacer pad can be rigid so that the spacer pad does not flex duringscanning. The spacer pad can be low weight. The spacer pad can bepositioned between at least one of an arm and trunk of the patient orlegs of the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of at least one embodiment are discussed below withreference to the accompanying figures, which are not intended to bedrawn to scale. The figures are included to provide illustration and afurther understanding of the various aspects and embodiments, and areincorporated in and constitute a part of this specification, but are notintended as a definition of the limits of the invention. In the figures,each identical or nearly identical component that is illustrated invarious figures is represented by a like numeral. For purposes ofclarity, not every component may be labeled in every figure. In thefigures:

FIG. 1 is a simplified and schematic cross-sectional elevationillustrating a fan-shaped distribution of x-rays in a DXA system inwhich lymphedema can be detected.

FIG. 2 illustrates a simplified and schematic perspective view of apatient with spacer pads according to an embodiment of the presentinvention.

FIG. 3 illustrates a projection image of a patient with spacer padstaken with a DXA system.

FIG. 4 illustrates a schematic perspective view of a spacer pad inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION

Except as otherwise noted, the articles “a,” “an,” and “the” mean “oneor more.”

FIG. 1 illustrates a DXA system 10. The DXA system 10 includes a patienttable 12 having a support surface 14 that can be considered horizontaland planar in this simplified explanation and illustration, which is notnecessarily accurate in scale or geometry and which is used here solelyto illustrate and explain certain principles of operation. A humanpatient 26 is supine on surface 14. The length of the patient is along ahorizontal longitudinal axis defined as the y-axis and the patient'sarms are spaced from each other along the x-axis. A C-arm 16 hasportions 16 a and 18 b extending below and above table 10, respectively,and is mounted in a suitable structure (not shown expressly) for movingat least parallel to the y-axis along the length of patient 26. Lowerportion 16 a of the C-arm carries an x-ray source 20 that can emitx-rays limited by an aperture 22 into a fan-shaped distribution 24conforming to a plane perpendicular to the y-axis. The energy range ofthe x-rays can be relatively wide, to allow for the known DXAdual-energy x-ray measurements, or can be filtered or generated in anarrower range to allow for single energy x-ray measurements. The x-raydistribution can be continuous within the angle thereof or can be madeup, or considered to be made up, of individual narrower beams. The x-raydistribution 24 can encompass the entire width of the patient asillustrated, or it can have a narrower angle so the entire patient canbe covered only by several passes along the y-axis and the x-raymeasurements from the several passes can be combined as is known in theart to simulate the use of a wider fan beam, as typical in currentcommercial DXA systems. Alternatively, a single, pencil-like beam ofx-rays can be used to scan selected regions of the patient's body, e.g.in a raster pattern. The x-rays impinge on x-ray detector 28, which cancomprise one or more linear arrays of individual x-ray elements 30, eachlinear array extending in the x-direction, or a continuous detectorwhere measurements for different positions along the detector can bedefined in some manner known in the art, or can be another form ofdetector of x-rays. C-arm 16 can move at least along the y-axis, or canbe maintained at any desired position along that axis. For any oneposition, or any one unit of incremental travel in the y-direction ofarm 16, detector 28 can produce one or several lines of raw x-ray data.Each line can correspond to a row of pixels in a resulting image, whichrow extends in a direction corresponding to the x-direction. Each linecorresponds to a particular position, or range of positions, of theC-arm in its movement along the y-axis and/or a particular lineardetector, and comprises a number of individual measurements, each for arespective detector element position in the line, i.e., representsattenuation that the x-rays have suffered in traveling from source 20 toa respective detector element position over a specified time interval. ADXA system takes a higher x-ray energy measurement H and a lower x-rayenergy measurement L from each detector element position, and carriesout initial processing known in the art to derive, from the raw x-raydata, a set of pixel values for a projection image. Each pixel valuecomprises a high energy value H and a low energy value L. This can beachieved by rapidly alternating the energy level of the x-rays fromsource 20 between a higher and a lower range of x-ray energies, forexample by rapidly rotating or otherwise moving a suitable filter in orout of the x-rays before they reach patient 26, or by controlling thex-ray tube output, and/or by using an x-ray detector 28 that candiscriminate between energy ranges to produce H and L measurements foreach pixel position, e.g., by having a low energy and a high energydetector element side-by-side or on top of each other for respectivepositions in the detector array. The H and L x-ray measurements for therespective pixel positions are computer-processed as known in the art toderive estimates of various parameters, including, if desired, bodycomposition (total mass, fat mass, and lean mass). Nonlimiting examplesof DXA systems include those described in U.S. Patent ApplicationPublication Nos. 2011/0235886 and 2011/0311122.

FIG. 2 illustrates spacing pads of such construction in use to space thearms of a patient from the torso. As the patient is prepared for theimage scan, each pad is placed between an arm and trunk of the patient,as high up into the armpit of the patient as is comfortable. Hands maybe positioned vertically, but not against the hips to enablevisualization of the arms cleanly cut from the trunk for analysis.Although not illustrated, it is appreciated that a spacer pad may alsobe positioned between the legs of the patient. FIG. 3 illustrates anexemplary scan which has been obtained using the spacing pads, andillustrating the clear delineation provided using the invention. FIG. 4illustrates an exemplary pad of the invention, encased for use in asanitary, disposable plastic bag.

Such an arrangement enables the clear delineation of the individual bodyparts of a patient, allowing for more accurate mass determinations forvarious body parts and facilitating the comparison of different massesbetween related appendages. As a result, lymphedema may be more rapidlyidentified and a patient may receive treatment before appreciableprogression of the chronic disease.

It is to be appreciated that embodiments of the methods and apparatusesdiscussed herein are not limited in application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the accompanying drawings. Themethods and apparatuses are capable of implementation in otherembodiments and of being practiced or of being carried out in variousways. Examples of specific implementations are provided herein forillustrative purposes only and are not intended to be limiting. Inparticular, acts, elements and features discussed in connection with anyone or more embodiments are not intended to be excluded from a similarrole in any other embodiment.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. Any references toembodiments or elements or acts of the systems and methods hereinreferred to in the singular may also embrace embodiments including aplurality of these elements, and any references in plural to anyembodiment or element or act herein may also embrace embodimentsincluding only a single element. The use herein of “including,”“comprising,” “having,” “containing,” “involving,” and variationsthereof is meant to encompass the items listed thereafter andequivalents thereof as well as additional items. References to “or” maybe construed as inclusive so that any terms described using “or” mayindicate any of a single, more than one, and all of the described terms.

All parts, ratios, and percentages herein, in the Detailed Descriptionand Claims are by weight and all numerical limits are used with thenormal degree of accuracy afforded by the art, unless otherwisespecified.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

It should be understood that every maximum numerical limitation giventhroughout this specification includes every lower numerical limitation,as if such lower numerical limitations were expressly written herein.Every minimum numerical limitation given throughout this specificationincludes every higher numerical limitation, as if such higher numericallimitations were expressly written herein. Every numerical range giventhroughout this specification includes every narrower numerical rangethat falls within such broader numerical range, as if such narrowernumerical ranges were all expressly written herein.

All documents cited herein are, in the relevant part, incorporatedherein by reference; the citation of any document is not to be construedas an admission that it is prior art with respect to the presentinvention. To the extent that any meaning or definition of a term or inthis written document conflicts with any meaning or definition in adocument incorporated by reference, the meaning or definition assignedto the term in this written document shall govern.

Having described above several aspects of at least one embodiment, it isto be appreciated various alterations, modifications, and improvementswill readily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to be part of thisdisclosure and are intended to be within the scope of the invention.Accordingly, the foregoing description and drawings are by way ofexample only.

What is claimed is:
 1. A system for analyzing a body composition of apatient comprising: a dual energy x-ray absorptiometry system comprisinga computer, x-ray source and a patient support platform, wherein thepatient support platform is configured to receive the patient in asupine position with the x-ray source disposed above the patient supportplatform and wherein the dual energy x-ray absorptiometry system isconfigured to scan the patient to measure the body composition; and oneor more spacer pads disposed within a field of view of the dual energyx-ray absorptiometry system, the one or more spacer pads configured tobe positioned between body parts of the patient; wherein the computerprocesses image information acquired with the dual energy x-rayabsorptiometry system and detects the one or more spacer pads to providean analysis of the body composition, such that the analysis of the bodycomposition does not include information about the one or more spacerpads.
 2. The system of claim 1, wherein the one or more spacer padscomprises low x-ray attenuation material.
 3. The system of claim 2,wherein the low x-ray attenuation material is radiographic foam.
 4. Thesystem of claim 1, wherein each of the one or more spacer pads isuniformly constructed.
 5. The system of claim 1 further comprising asanitary cover to cover each of the one or more spacer pads, thesanitary cover made of clear material.
 6. The system of claim 1, whereina height of each of the one or more spacer pads exceeds a maximum bodythickness of the patient.
 7. The system of claim 1, wherein the one ormore spacer pads is rigid so that the one or more spacer pads does notflex during use.
 8. The system of claim 1, wherein the one or morespacer pads is positioned between at least one of an arm and torso ofthe patient and legs of the patient.
 9. A method of analyzing a bodycomposition of a patient comprising: providing a dual energy x-rayabsorptiometry system, the system comprising a computer x-ray source anda patient support platform; positioning the patient in a supine positionon the patient support platform such that the patient is between thex-ray source and the patient support platform; positioning a spacer padbetween body parts of the patient such that the spacer pad is positionedwithin a field of view of the dual energy x-ray absorptiometry system;scanning the patient with the dual energy x-ray absorptiometry system tomeasure the body composition; and computer processing image informationacquired from the scanning step and detecting the spacer pad to providean analysis of the body composition, such that the analysis of the bodycomposition does not include information about the spacer pad.
 10. Themethod of claim 9 further comprising scanning the patient using the dualenergy x-ray absorptiometry system to detect lymphedema.
 11. The methodof claim 9, wherein the spacer pad comprises low x-ray attenuationmaterial.
 12. The method of claim 11, wherein the low x-ray attenuationmaterial is radiographic foam.
 13. The method of claim 9, wherein thespacer pad is uniformly constructed.
 14. The method of claim 9, whereinthe spacer pad is covered by a sanitary cover, the sanitary cover madeof clear material.
 15. The method of claim 9, wherein a height of eachof the one or more spacer pads exceeds a maximum body thickness of thepatient.
 16. The method of claim 9, wherein the spacer pad is rigid sothat the spacer pad does not flex during scanning.
 17. The method ofclaim 9, wherein the spacer pad is positioned between at least one of anarm and torso of the patient or legs of the patient.